TB 1-1520-238-20-99
f. Component/Parts in Stock at All Levels (Depot and Others) Including War Reserves. Upon receipt
of this TB, the material condition tags of all items in all condition codes listed in paragraph 6 shall be annotated
to read, "TB 1-1520-238--20-99, One Time Inspection of the Main Transmission Not Complied With."
(1) Wholesale Stock. Report receipt of this TB in accordance with paragraph 14.c(1). Upon re-
ceipt of this TB, all serviceable items (condition codes //A//, //B//, //C//, //D//, and //E//) listed in paragraph 6
located in wholesale depot storage shall be placed in condition code //J// and tagged with a suspended tag/la-
bel----Material, DD Form 1576/DD Form 1576-1. Do not remove original condition tags. Report compliance
with this TB in accordance with paragraph 14.d(1).
(2) Retail Stock. Report receipt of this TB in accordance with paragraph 14.c(2). Upon receipt
of this TB, commanders and others maintaining retail stock at installation level and below shall contact the
supported aviation unit to perform the inspection required by paragraph 8 and the correction procedures of
paragraph 9 on discrepant materiel. Disposition of discrepant materiel will be in accordance with paragraph
10. Report compliance of this TB in accordance with paragraph 14.d(2).
g. Components/Parts in Work (Depot Level and Others). Items listed in paragraph 6 in work will not
be issued until compliance with this TB.
2.
Task/Inspection Suspense Date. Prior to next flight.
3.
Reporting Compliance Suspense Date. N/A.
4.
Summary of the Problem.
a. A recent accident was caused by a simultaneous in-flight dual failure of both the primary and secon-
dary over running clutches inside the main transmission accessory gearbox. This failure resulted in the loss
of all AC electrical, primary and hydraulic systems, and pressurized air system.
b.
For manpower/downtime and funding impacts, see paragraph 12.
c.
The purpose of this TB is to:
(1) Require a one time inspection of all AH-64 main transmissions.
(2) Establish a retirement life of 750 flight hours for the primary and secondary clutch assemblies
inside the accessory gearbox portion of the main transmission.
(3) Establish additional criteria for main transmission removal.
(4) Establish a change to the --10 Operator's Manual.
5.
End Items To Be Inspected .
All AH-64 series aircraft.
Assembly Components To Be Inspected.
NOMENCLATURE
PART NUMBER
NATIONAL STOCK NUMBER
Main Transmission
7-311310001/-5
1615-01-165--9452
Main Transmission
7-311310001-25
Main Transmission
7--311310001-27
Main Transmission
7-311310001-33
Main Transmission
7-311310001-35
Main Transmission
7-311310001-37/-39
Main Transmission
7-311310001-43
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